Pile Forces in Integral Abutment Bridges Subjected to Truck Loads

Abstract

Interest in the use of integral bridges has increased in recent years because of their economy, reliability, and strength. However, most of the published research on integral bridges has been concerned with determination of the thermal effect, creep analysis, and seismic behavior. Few studies on live load analysis of integral abutment bridges have been carried out. The pile load behavior of integral abutments supporting composite steel superstructures subjected to gravity loads is investigated. The applied loading is composed of one or more side-by-side HS20-44 trucks. The finite element method is used to analyze the three-dimensional bridge system and determine forces in the piles. A parametric study is performed to obtain the effects of the number of trucks and their location, superstructure geometry, pile spacing and stiffness, pile connection type, and wingwall length on the pile loads. A simple, approximate procedure for computing pile loads is developed on the basis of the findings of the finite element analysis. The results indicate that the abutment-wingwall system does not behave as a rigid block as in the conventional case of a footing on flexible piles. Also, the generated bending moment in the piles caused by gravity load is significant and cannot be neglected in design.